Rotary disc bit



1959 o. HAM-MER 2,898,089

ROTARY DISC BIT Filed May 2, 1955 IN V EN TOR. 0770 AQMMEZ ROTARY DISC BIT Otto Hammer, Whittier, Calif., assignor to Dresser Operations, Inc., Dallas, Tex., a corporation of California Application May 2, 1955, Serial No. 505,150'

3 Claims. (Cl. 255-323) This invention relates to improvements in rotary earth- Explanatory of the present invention, in the making of seismographic investigations of prospective oil fields it has been customary to drill a number of relatively shallow holes in the earth in which explosives are detonated, from which certain observations are made. These holes are usually of small diameter and are drilled as rapidly and as inexpensively as possible. In other investigations of prospective oil fields the practice of slim hole drilling has been employed wherein a bore of relatively small diameter is drilled as inexpensively and as rapidly as possible to the depth of anticipated production. In both of these practices it is desirable to employ a bit of the rotary cutter type. However, a small sized bit of the conventionaldisc cutter type is unsuitable due to the inability to provide adequate bearings for the cutters that will carry the loads of the heavy weights employed.

It is, therefore, a more specific object of the invention to provide a rotary earth-boring bit wherein rotary cutters of a size to provide adequate bearings are employed and wherein the bit is made up of two opposed halves which are rigidly secured together. Each half or segment of the body carries a downwardly extending arm on the inner side of which there is a cutter pin or cutter journal. The inner ends of the cutter pins or cutter journals preferably mutually contact with each other and the cutters are assembled on the cutter pins prior to the assemblyof the opposed halves of the body. In this manner, the disclike cutters may mutually contact with each other atthe center of the bit and may provide inner cutting edges which are very close to each other and which can be advantageously utilized to cut up or abrade away the core that is left in the formation by the outer or principal cutting edges of the "cutters. The inner ends of the cutters may also be so formed or, shaped as to fit closely about the inner "ends of the cutter pins or cutter journals and these closely fitting portions together with the arms of the body may serve to confine roller bearings or other bearings which maybe made of adequate size to zga y avy loads that rr ay be imposed on the bit. n i9 Offill bi is a sg d a ousin ha it facilitates the application of hard facing to portions of the arms and to the cutters that are in mutual engagement with each other to provide adequate friction bearings. The construction also enables hard facing to be applied to the mutually engaging faces of the cutters to provide adequate friction bearings at this point.

With the foregoing and other objects in view, which will be made manifest in the following detailed description, and specifically pointed out in the appended claims,

' United States Patent tions of the cutter pins. or

Patented Aug, 4, 1959 reference is had to the accompanying drawings for an illustrative embodiment of the invention, wherein:

Figure l is a view in side elevation of the bit embodying the present invention, parts being broken away and shown in vertical section;

Fig. 2 is a bottom plan view of the bit shown in Fig. 1;

Fig. 3 is a horizontal section taken substantially upon the line 33 upon Fig. l in the direction indicated;

Fig. 4 is a view in side elevation of a modified form of cutter that may be employed; and A Fig. 5 is a vertical section taken substantially upon the line 5-5 upon Fig. 4.

Referring to the accompanying drawings wherein similar reference characters designate similar parts throughout, the improved bit comprises a body made'up of two opposed complementary halves 10 and 11. Each of these halves has a downwardly extending arm integral therewith, the arm for the half 10 being indicated at 12 and the arm for the half 11 being indicated at 13. As indicated on Fig. 2, these arms as they extend downwardly are slightly offset with respect to each other, that is, the arm 12 extends forwardly with respect to a transverse center line A--B (see Figs. 2 and 3) and the arm 13 extends rearwardly with respect to the same center line. Adjacent the lower ends of each of the arms there are inwardly extending cutter pins or cutter journals 15. These are preferably formed integral with their respective arms. On the cutter pins there are rotatably mounted disc-like cutters 16 and 17. These cutters mutually engage with each other on a central plane indicated at 18, and have their inner portions 19 so formed as to fit closely about the mutually contacting inner ends of the cutter pins or cutter jounrals 15. Outwardly of these closely fitting portions 19 the interiors of the cutters are enlarged to accommodate rollers 20 of anti-friction roller bearings. While roller bearings are preferably employed, friction type bearings may be employed in lieu thereof. With this arrangement wherein the cutters serve to con, fine the roller bearings or other bearings on the cutter pins or journals 15 and the arms 12 and 13 are also employed to confine the bearings, the bearings may be made of adequate size to withstand the heavy loads that may be imposed. If roller bearings are employed the individual rollers can be made relatively large, even though the gauge of the bit and the size of the disc-like cutters is relatively small.

On the inner faces of the arms 12 and 13 around the which are in mutual contact with each other formfriction bearings between the outer faces of the cutters and the arms capable of carrying lateral loads that may be imposed on the cutters. In a similar, manner, the opposed mutually contacting faces at 18 on thecutters may be grooved and filled with hard facing as indicated at 23. These rings of hard facing will be mutually eccentric with respect to each other due to the offset positions of the arms 12 and 13 and, consequently, the offset posijournals 15 with respect ;to each other. Nevertheless, regardless ,of their eccentric relationship to eachother they will provide a type of friction bearing between the mutually engaging surfaces between the two cutters.

At the outer sides of the cutters there are outer or principal cutting edges 24 which extend circumferentially. These may be protected by hard facing applied thereto as by welding, as indicated at 25. These cutting edges in the form illustrated in Fig. 1 are circumferentially continuous, but in the form illustrated in Figs. 4 and 5 they are circumferentially interrupted so as to divide the cutting edge into teeth indicated at 26. The particular 7 shape or configuration of the outer or principal cutting edges of the disc-like cutters is immaterial insofar as the present invention is concerned. 7

'Adjacent the mutually contacting faces 18 there are annular ridges formed on the cutters which may be protected by having tungsten carbide inserts 27 applied there to as by welding These ridges or inner cutting edges can be located very close to each other by reason of the mutually contacting surfaces at 18. Consequently, these inner cutting edges can very efficiently cut or abrade away the central core that is left in the formation by the outer cutting edges 24 or the cutting teeth 26, as the case may be.

The opposed faces of the body halves and 11 are channelled as indicated at 28 and 29, respectively. These channels mutually cooperate to form a circulation passage for conducting circulation fluid that is discharged through nozzles 30 and 31 that are recessed in the body halves 10 and 11, respectively.

In assembling the bit, the cutters and their respective bearings are positioned on the cutter pins or journals of the two body halves 10 and 11 and the two body halves are then welded together with seam welds indicated at 32. Various means may be employed for holding the two body halves in proper alignment with each other during the welding, such as, for example, the dowel 33 which is received in blind holes drilled in opposed halves of the bit.

2,89 ,089 r r A A i said parallel faces having hardened bearing surfaces, sai

When the body halves have been welded together the conventional threaded pin can be turned on the top of the body thus formed. Any other means may be employed for holding the two body halves and their associated structure in proper alignment with respect to each other while the welding is being performed.

From the above-described construction it will be appreciated that it is possible to very easily construct the two body halves, the cutters, and to hard face the cutters and arms and to assemble the various parts together. Adequate provision is made for removing the central core that is left in the formation by the principal cutting edges, although the bit may be of very small size, such as, for example, a 2%" bit. There is adequate opportunity to use relatively large bearings or rollers 20 within the cutters. In this manner, the heavy loads or weights imposed on the bit are easily carried. The improved bit while primarily designed for drilling rapidly the small diameter holes used in seismographic investigations and in slim hole drilling, maybe also advantageously employed in drilling holes of larger or conventional size.

Various changes may be made in the details of construction without departing from the spirit or scope of the invention as defined by the appended claims.

I claim:

1. A rotary well drilling bit comprising a body composed of two opposed halves mutually secured together, each half having a downwardly extending arm, the arms being arranged on opposite sides of a vertical central axis through the body about which the body is adapted to be rotated, cutter journals on the inner sides of the arms extending towards each other upon substantially parallel but disaligned horizontal axes, said cutter journals having their inner ends in mutual contact, disc shaped cutters rotatably mounted upon the cutter journals, said disc shaped cutters having parallel faces in mutual contact with each other and presenting inner cutting edges adjacent the plane of mutual contact between the cutters,

inner cutting edges of said cutters having hardened cutting faces thereon said cutters presenting outer cutting edges of greater diameter than the inner cutting edges which are rigid with the inner cutting edges and which are disposed more remote from the plane of mutual contact whereby upon rotation of the body about its vertical central axis the outer cutting edges will tend to disc the formation encountered and tend to forcibly rotate the inner cutting edges to remove the core left between the outer cutting edges. T

2. A rotary well drilling bit comprising a body rotatable about its vertical central axis, said body having downwardly extending arms arranged on opposite sides of said axis, substantially horizontal cutter journals extending inwardly from said arms towards said axis, disc-type cutters rotatable on the cutter journals, said cutters being in mutual contact adjacent said axis, each cutter presenting an inner cutting edge adjacent the plane of mutual contact between the cutters and an outer cutting edge rigid therewith but more remote therefrom, the mutually'contacting faces of the cutters having rings of hard facing recessed therein, the outer cutting edge being of greater diameter than the inner cutting edge whereby as the body of the bit is rotated the outer cutting edges because of their engagement with the formation and because of their diameters will tend to forcibly rotate the cutters thus causing the inner cutting edges to rotate and remove the core left between the outer cutting edges.

3. A rotary well drilling bit comprising a body rotatable about its vertical central axis, said body having downwardly extending arms on opposite sides of said axis, cutter journals extending from said arms, disc-type cutters rotatably mounted upon said journals for rotation about substantially horizontal axes, said cutters mutually-engaging each other adjacent said axis, each cutter presenting an inner cutting edge adjacent the plane of mutual contactbetween the cutters and an outer cutting edge rigid therewith but more remote therefrom, the outer cutting edge having a greater diameter than the inner cutting edge, there being portions of each cutter between the cutting edges having less diameter than either cutting edge whereby as the body is rotated the outer cutting edges because of their engagement with the formation and their large diameter will cause the cutters to rotate thus causing the inner cutting edges to rotate and cut away the core left between the outer cutting edges, said cutters having a stepped bore, the smaller diameter portion of the bore being of approximately the diameter of the journal, the larger diameter portion of the bore being substantially in the plane of the larger diameter of the-cutter, and roller bearings between said larger diameter bore portion and the journal, the smaller diameter portion of the bore and the body arm forming an enclosure for the bearings.

References Cited in the file of this patent UNITED STATES PATENTS 1,203,112 Harris et al. Oct. 31, 1916 1,592,258 Deakins July 13, 1926 1,932,489 Scott Oct. 31, 1933 1,992,350 Black Feb. 26, 1935 2,047,112 Reed July 7, 1936 2,050,988 Zublin Aug. 11, 1936 2,133,022 Fisher Oct. 11, 1938 2,201,379 Shaw June 2, 1939 2,184,066 Zublin Dec. 19, 1939 

